For any reasonable company (even a single founder one), 300eur is nothing
With this limitation, many developers simply do not (and rightly so) put the effort in accepting anything in that ballpark because it's just extra work.
I'm pretty sure in most EU countries the profitability of a service supported by patreon (that is, a passive income in sub 10k range) would be almost nullified if correctly accounted for taxation.
I had long discussions with friends about legally accepting money for side projects. It's a very hard topic to discuss.
I'd be curious to know if anybody in an EU country is able to legally accept and declare a side income and retain anything more than 30%.
And yes, I know that VAT isn't required piece of information on all invoices, but it WILL make the payment go smoother through the accounting departments which is what you want ;)
AFAIK the big problem with VAT, from a seller perspective, is the fact that most governments, knowing full well that 90% of businesses fail in the first 2 years, ask for big upfront payments on estimate VAT remittances in that window, to make sure they don't lose out. After 3 years, as long as your accountancy is correct, it should be smooth sailing.
There are other way to start companies that are not directly attached to a person, but this involves a much larger upfront capital, which is designed to avoid exactly this scenario.
For a realistic example in Italy, having a VAT number implies a minimal fixed yearly cost of ~300eur (combining all various expenses) even for zero income. If you already are an employee, any extra income is likely to be taxed higher and require extra bookkeeping, to the point that cost parity is only attained if you can invoice for at least 450-500 eur.
This is purely wasted money, without considering the extra work that you have to put into for the tax records.
It's simply not worth it.